Advanced Navy systems for underwater communications, ranging, detection, and surveillance heavily depend on the availability of blue-green efficient lasers. No lasers have been disclosed which operate in the blue-green spectral region within that band of wavelengths known as the "ocean window" wherein light energy transmittance is achieved through ocean waters with the least attenuation.
Photodissociation of a parent molecule into excited fragments for the purpose of generating a population inversion has been used successfully in the past for laser action. The first laser based on excitation by photodissociation was reported by Kaspers and Pimental (Applied Physics Letters 5, 231 (1964) who achieved lasing at 1.315.mu. in atomic iodine by dissociating either CH.sub.3 I or CF.sub.3 I. Most subsequently reported laser transitions based on this principle of excitation occurred also in the infrared spectral region, either between atomic states like Br, K, Rb and Cs or between rotational-vibrational levels of molecular electronic ground states like NO or CN. Only very recently, a visible atomic transition in In at 451 nm was reported by R. Burnham in Applied Physics Letters, 30, 132 (1977).